The influence of incorporating organic molecules or inorganic nanoparticles on the optical and electrical properties of carbon nanotube films

Organic molecules and inorganic nanoparticles were incorporated into transparent and conductive single- or double-wall carbon nanotube (SWNT or DWNT) films, and their electrical and optical properties were measured. When organic tetrafluoro-tetracyanoquinodimethane (F4TCNQ) molecules were incorporated into the nanotube films, sheet resistance was reduced to ∼50% of those from the pristine SWNT and DWNT films. Larger improvements were observed with Au nanoparticle decoration or HNO3/SOCl2 dipping processes. The sheet resistances were measured to be 42Ω/sq at 75% of transmittance for HNO3/SOCl2-treated DWNT films and 64Ω/sq at 77% for Au-incorporated DWNT films, making their electrical conductivities 200%–300% better than those of the pristine DWNT films. It was observed that DWNTs have better electrical/optical performance than SWNTs. The relative influence of various dopants, F4TCNQ, Au, and HNO3/SOCl2 as well as microwave irradiation on the optical and electrical properties was identified by using Raman and UV-vis-NIR spectra.

► Organic and inorganic nanomaterials were employed for p-type doping of carbon nanotube films.
► Doped double-wall nanotube films yielded high electrical conductivities up to ∼6×105 S/m.
► Excellent sheet resistance, 42Ω/sq at 75% of transmittance was observed.
► Microwave irradiation is suggested to create sites for doping.